Return value from php to javascript

Question

I writing a registration/login form, I am sending user info via POST to a PHP that is looking in a DB. I would like that the PHP returns an ok or wrong value to the js and I don't now how to do it. Here my js:

    ui.onClick_regsubmit=function()
{
var fname=document.getElementById('fname').value;
var lname=document.getElementById('lname').value;
var password=document.getElementById('password').value;
var mail=document.getElementById('mail').value;
var affiliation=document.getElementById('affiliation').value;
var data = new FormData();
var xhr = (window.XMLHttpRequest) ? new XMLHttpRequest() : new activeXObject("Microsoft.XMLHTTP");
data.append("fname",fname);
data.append("lname",lname);
data.append("password",password);
data.append("mail",mail);
data.append("affiliation",affiliation);
xhr.open( 'post', 'PHP/registration.php', false );
xhr.send(data);
window.alert(affiliation);
}

And the php:

<?php
     mysql_connect('localhost','root','') or die('Cannot connect mysql server');
       mysql_select_db('ChemAlive_login')  or die('cannot connect database');

   $lname=$_POST['lname'];
   $fname=$_POST['fname'];
  $password=$_POST['password'];
  $mail=$_POST['mail'];
  $affiliation=$_POST['affiliation'];

  $q=mysql_query("select * from login where mail='".$mail."' ") or die(mysql_error());
  $n=mysql_fetch_row($q);
  if($n>0)
{
  $q=mysql_query("select password  from login where mail='".$mail."' ");
  $pp=mysql_fetch_row($q);
  if($pp[0]=$password) echo "ok";
  else echo "wrong";
}
else
{   $insert=mysql_query("insert into login values('".$fname."','".$lname."','".$mail."','".$password."','".$affiliation."')") or die(mysql_error());}
?>

I would like to return to js this ok or wrong value. How to do it?

Анатолий Грабаров · Accepted Answer · 2015-03-23 17:54:01Z

1

xhr.onload=function()
{
 if (xhr.status==200) 
 {
  alert(xhr.response);
 }else
 {
  alert("unknown server error");
 }
}

it will be better if the server sends a response code, and javascript will transfer this code to the text. For example:

onload=function()
{
 switch(xhr.response)
 {
  case "0":{alert("unknown error")};break;
  case "1":{alert("email is already used")};break;
  ...
 }
}

I think thought it is clear

answered Mar 23, 2015 at 17:54

Анатолий Грабаров

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Comments

Rufus · Accepted Answer · 2015-03-23 17:51:29Z

I do not have the rep to comment or I'd ask for details, but if you can consider using ajax, it could look something like this:

php:

$doit = //your query;
if($doit){
$youdid = 'ok';
}
else{
exit('1');
}

js:

$(document).ready(function () {

            var foo = $("#formfield")val();
            $.ajax({
                "foo":foo;
                type: 'POST',
                url: 'some.php',
                success: function(responseText) { 
if(responseText == "1") {
alert("Leave instantly");
};

}
else {
alert("One of us");
}

nothing123456 · Accepted Answer · 2015-03-23 18:36:03Z

If you want to return either ok or wrong to the JavaScript to handle you could do something like this in your registration.php page:

 $q=mysql_query("select password  from login where mail='".$mail."' ");
 $pp=mysql_fetch_row($q);
   if($pp[0]=$password){ 
     header('Content-Type: application/json');
         echo json_encode(array('password' => 'ok'));
   }else{ 
     header('Content-Type: application/json');
         echo json_encode(array('password' => 'wrong'));
   }

I have not fully testing this, but the idea is to set the header to return json and then send it a JSON string.

Does that make sense?

Like I said in my comment below I have only used jQuery for AJAX. But here is a little something of what I know about XMLHttpRequest and my undertsanding of how you would test what you get back.

You can set up a listener for when you get a response back onreadystatechange and then put the response in a variable var pass = xhr.response and then just output the text to an alert box like alert(pass.password).

if (xhr.onreadystatechange === 4 && xhr.status === 200){
    var pass = xhr.response;
    //should output either ok or wrong
    alert(pass.password);
}

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